diff --git a/.gitignore b/.gitignore
new file mode 100644
index 0000000..fad4507
--- /dev/null
+++ b/.gitignore
@@ -0,0 +1,12 @@
+# wiki files
+Python2017.wiki/*
+
+# Jupyter Files
+*/.ipynb_checkpoints/*
+
+# Rope files
+.ropeproject
+*/.ropeproject
+
+# Labs temp files
+labs03/haslo2.txt
diff --git a/labs03/Podstawy 2.ipynb b/labs03/Podstawy 2.ipynb
index 53da94e..adf5795 100644
--- a/labs03/Podstawy 2.ipynb	
+++ b/labs03/Podstawy 2.ipynb	
@@ -49,22 +49,34 @@
   },
   {
    "cell_type": "code",
-   "execution_count": null,
+   "execution_count": 9,
    "metadata": {
     "slideshow": {
      "slide_type": "slide"
     }
    },
-   "outputs": [],
+   "outputs": [
+    {
+     "name": "stdout",
+     "output_type": "stream",
+     "text": [
+      "2\n",
+      "[1, 2, 3, 1, 2, 3]\n",
+      "123\n"
+     ]
+    }
+   ],
    "source": [
-    "def dwojak(x): x *= 2\n",
+    "def dwojak(x): \n",
+    "    x *= 2\n",
+    "    return x\n",
     "    \n",
     "l = [1, 2, 3]\n",
     "s = \"123\"\n",
     "\n",
     "dwojak(l)\n",
     "dwojak(s)\n",
-    "\n",
+    "print(dwojak(1))\n",
     "print(l)\n",
     "print(s)"
    ]
@@ -104,16 +116,28 @@
   },
   {
    "cell_type": "code",
-   "execution_count": null,
+   "execution_count": 11,
    "metadata": {
     "slideshow": {
      "slide_type": "slide"
     }
    },
-   "outputs": [],
+   "outputs": [
+    {
+     "name": "stdout",
+     "output_type": "stream",
+     "text": [
+      "[1, 2, 3, 1, 2, 3]\n",
+      "F: [1, 2, 3, 1, 2, 3]\n",
+      "[1, 2, 3]\n"
+     ]
+    }
+   ],
    "source": [
     "def dwojak1(x): x *= 2\n",
-    "def dwojak2(x): x = x * 2\n",
+    "def dwojak2(x): \n",
+    "    x = x * 2\n",
+    "    print(\"F:\", x)\n",
     "\n",
     "l = [1,2, 3]\n",
     "dwojak1(l)\n",
@@ -126,29 +150,47 @@
   },
   {
    "cell_type": "code",
-   "execution_count": null,
+   "execution_count": 17,
    "metadata": {
     "slideshow": {
      "slide_type": "slide"
     }
    },
-   "outputs": [],
+   "outputs": [
+    {
+     "name": "stdout",
+     "output_type": "stream",
+     "text": [
+      "[1, 2, 3]\n",
+      "[1, 2, 3, 4]\n"
+     ]
+    }
+   ],
    "source": [
     "l = [1, 2, 3]\n",
-    "e = l\n",
+    "e = l[:]\n",
     "e.append(4)\n",
-    "print(l)"
+    "print(l)\n",
+    "print(e)"
    ]
   },
   {
    "cell_type": "code",
-   "execution_count": null,
+   "execution_count": 19,
    "metadata": {
     "slideshow": {
      "slide_type": "slide"
     }
    },
-   "outputs": [],
+   "outputs": [
+    {
+     "name": "stdout",
+     "output_type": "stream",
+     "text": [
+      "[[1], [1], [1]]\n"
+     ]
+    }
+   ],
    "source": [
     "e = []\n",
     "f = [e for i in range(3)]\n",
@@ -172,18 +214,39 @@
   },
   {
    "cell_type": "code",
-   "execution_count": null,
+   "execution_count": 25,
    "metadata": {
     "slideshow": {
      "slide_type": "slide"
     }
    },
-   "outputs": [],
+   "outputs": [
+    {
+     "name": "stdout",
+     "output_type": "stream",
+     "text": [
+      "(1, 'napis', [0])\n",
+      "3\n"
+     ]
+    },
+    {
+     "ename": "TypeError",
+     "evalue": "unhashable type: 'list'",
+     "output_type": "error",
+     "traceback": [
+      "\u001b[0;31m---------------------------------------------------------------------------\u001b[0m",
+      "\u001b[0;31mTypeError\u001b[0m                                 Traceback (most recent call last)",
+      "\u001b[0;32m<ipython-input-25-2bd2fa17fbf5>\u001b[0m in \u001b[0;36m<module>\u001b[0;34m()\u001b[0m\n\u001b[1;32m      3\u001b[0m \u001b[0mprint\u001b[0m\u001b[0;34m(\u001b[0m\u001b[0mt\u001b[0m\u001b[0;34m)\u001b[0m\u001b[0;34m\u001b[0m\u001b[0m\n\u001b[1;32m      4\u001b[0m \u001b[0mprint\u001b[0m\u001b[0;34m(\u001b[0m\u001b[0mlen\u001b[0m\u001b[0;34m(\u001b[0m\u001b[0mt\u001b[0m\u001b[0;34m)\u001b[0m\u001b[0;34m)\u001b[0m\u001b[0;34m\u001b[0m\u001b[0m\n\u001b[0;32m----> 5\u001b[0;31m \u001b[0mprint\u001b[0m\u001b[0;34m(\u001b[0m\u001b[0;34m{\u001b[0m\u001b[0mt\u001b[0m\u001b[0;34m:\u001b[0m \u001b[0;32mNone\u001b[0m\u001b[0;34m}\u001b[0m\u001b[0;34m)\u001b[0m\u001b[0;34m\u001b[0m\u001b[0m\n\u001b[0m",
+      "\u001b[0;31mTypeError\u001b[0m: unhashable type: 'list'"
+     ]
+    }
+   ],
    "source": [
-    "t = (1, \"napis\", None)\n",
-    "elem = t[0]\n",
+    "t = (1, \"napis\", [])\n",
+    "t[-1].append(0)\n",
     "print(t)\n",
-    "print(len(t))"
+    "print(len(t))\n",
+    "print({t: None})"
    ]
   },
   {
@@ -199,19 +262,29 @@
   },
   {
    "cell_type": "code",
-   "execution_count": null,
+   "execution_count": 36,
    "metadata": {
     "slideshow": {
      "slide_type": "fragment"
     }
    },
-   "outputs": [],
+   "outputs": [
+    {
+     "name": "stdout",
+     "output_type": "stream",
+     "text": [
+      "15\n",
+      "a == 1\n",
+      "b == (3, 4)\n"
+     ]
+    }
+   ],
    "source": [
     "def suma(*args):\n",
     "    return sum(args)\n",
     "print(suma(1,2,3,4,5))\n",
     "\n",
-    "def greet_me(**kwargs):\n",
+    "def greet_me(z=None,**kwargs):\n",
     "    if kwargs is not None:\n",
     "        for key, value in kwargs.items():\n",
     "            print(\"%s == %s\" %(key,value))\n",
@@ -231,16 +304,32 @@
   },
   {
    "cell_type": "code",
-   "execution_count": null,
+   "execution_count": 38,
    "metadata": {
     "slideshow": {
      "slide_type": "fragment"
     }
    },
-   "outputs": [],
+   "outputs": [
+    {
+     "name": "stdout",
+     "output_type": "stream",
+     "text": [
+      "97\n",
+      "a\n",
+      "98\n",
+      "b\n",
+      "99\n",
+      "c\n",
+      "100\n",
+      "d\n"
+     ]
+    }
+   ],
    "source": [
     "def alfaRange(x, y):\n",
     "    for i in range(ord(x), ord(y)):\n",
+    "        print(i)\n",
     "        yield chr(i)\n",
     "\n",
     "for c in alfaRange('a', 'e'):\n",
@@ -260,40 +349,74 @@
   },
   {
    "cell_type": "code",
-   "execution_count": null,
+   "execution_count": 45,
    "metadata": {
     "slideshow": {
      "slide_type": "fragment"
     }
    },
-   "outputs": [],
+   "outputs": [
+    {
+     "name": "stdout",
+     "output_type": "stream",
+     "text": [
+      "W Paryżu najlepsze kasztany są na placu Pigalle\n",
+      "Zuzanna lubi je tylko jesienią.\n",
+      "\n",
+      ">>\n"
+     ]
+    }
+   ],
    "source": [
     "plik = open(\"haslo.txt\", 'r')\n",
     "for linia in plik.readlines():\n",
     "    print(linia.strip())\n",
     "print(plik.read())\n",
+    "print(\">>\")\n",
     "plik.close()"
    ]
   },
   {
    "cell_type": "code",
-   "execution_count": null,
+   "execution_count": 47,
    "metadata": {
     "slideshow": {
      "slide_type": "slide"
     }
    },
-   "outputs": [],
+   "outputs": [
+    {
+     "name": "stdout",
+     "output_type": "stream",
+     "text": [
+      "W Paryżu najlepsze kasztany są na placu Pigalle\n",
+      "\n",
+      "Zuzanna lubi je tylko jesienią.\n",
+      "\n"
+     ]
+    },
+    {
+     "ename": "ValueError",
+     "evalue": "I/O operation on closed file.",
+     "output_type": "error",
+     "traceback": [
+      "\u001b[0;31m---------------------------------------------------------------------------\u001b[0m",
+      "\u001b[0;31mValueError\u001b[0m                                Traceback (most recent call last)",
+      "\u001b[0;32m<ipython-input-47-f06513c1bbec>\u001b[0m in \u001b[0;36m<module>\u001b[0;34m()\u001b[0m\n\u001b[1;32m      2\u001b[0m     \u001b[0;32mfor\u001b[0m \u001b[0mlinia\u001b[0m \u001b[0;32min\u001b[0m \u001b[0mplik\u001b[0m\u001b[0;34m.\u001b[0m\u001b[0mreadlines\u001b[0m\u001b[0;34m(\u001b[0m\u001b[0;34m)\u001b[0m\u001b[0;34m:\u001b[0m\u001b[0;34m\u001b[0m\u001b[0m\n\u001b[1;32m      3\u001b[0m         \u001b[0mprint\u001b[0m\u001b[0;34m(\u001b[0m\u001b[0mlinia\u001b[0m\u001b[0;34m)\u001b[0m\u001b[0;34m\u001b[0m\u001b[0m\n\u001b[0;32m----> 4\u001b[0;31m \u001b[0mprint\u001b[0m\u001b[0;34m(\u001b[0m\u001b[0mplik\u001b[0m\u001b[0;34m.\u001b[0m\u001b[0mread\u001b[0m\u001b[0;34m(\u001b[0m\u001b[0;34m)\u001b[0m\u001b[0;34m)\u001b[0m\u001b[0;34m\u001b[0m\u001b[0m\n\u001b[0m",
+      "\u001b[0;31mValueError\u001b[0m: I/O operation on closed file."
+     ]
+    }
+   ],
    "source": [
     "with open(\"haslo.txt\", 'r') as plik:\n",
     "    for linia in plik.readlines():\n",
     "        print(linia)\n",
-    "# print(plik.read())"
+    "print(plik.read())"
    ]
   },
   {
    "cell_type": "code",
-   "execution_count": null,
+   "execution_count": 48,
    "metadata": {
     "collapsed": true,
     "slideshow": {
@@ -334,13 +457,22 @@
   },
   {
    "cell_type": "code",
-   "execution_count": null,
+   "execution_count": 49,
    "metadata": {
     "slideshow": {
      "slide_type": "fragment"
     }
    },
-   "outputs": [],
+   "outputs": [
+    {
+     "name": "stdout",
+     "output_type": "stream",
+     "text": [
+      "posix\n",
+      "Nazwa uzytkownika: tomaszd\n"
+     ]
+    }
+   ],
    "source": [
     "import os\n",
     "print(os.name)\n",
@@ -351,13 +483,31 @@
   },
   {
    "cell_type": "code",
-   "execution_count": null,
+   "execution_count": 50,
    "metadata": {
     "slideshow": {
      "slide_type": "slide"
     }
    },
-   "outputs": [],
+   "outputs": [
+    {
+     "name": "stdout",
+     "output_type": "stream",
+     "text": [
+      "Counter({'o': 4, 'n': 4, 'a': 4, 'k': 3, 't': 3, 'y': 2, 'i': 2, 'c': 2, 'z': 2, 's': 1, 'p': 1, 'l': 1, 'ń': 1, 'w': 1, 'e': 1})\n"
+     ]
+    },
+    {
+     "data": {
+      "text/plain": [
+       "array([[ 1.,  3.,  4.,  5.]], dtype=float32)"
+      ]
+     },
+     "execution_count": 50,
+     "metadata": {},
+     "output_type": "execute_result"
+    }
+   ],
    "source": [
     "from collections import *\n",
     "print(Counter(\"konstantynopolitańczykowianeczka\"))\n",
@@ -394,13 +544,23 @@
   },
   {
    "cell_type": "code",
-   "execution_count": null,
+   "execution_count": 51,
    "metadata": {
     "slideshow": {
      "slide_type": "fragment"
     }
    },
-   "outputs": [],
+   "outputs": [
+    {
+     "name": "stdout",
+     "output_type": "stream",
+     "text": [
+      "What's your name?\n",
+      "Tomasz\n",
+      "Welcome home, Tomasz.\n"
+     ]
+    }
+   ],
    "source": [
     "name = input(\"What's your name?\\n\")\n",
     "print(\"Welcome home, {}.\".format(name))"
diff --git a/labs03/haslo.txt b/labs03/haslo.txt
new file mode 100644
index 0000000..f269661
--- /dev/null
+++ b/labs03/haslo.txt
@@ -0,0 +1,2 @@
+W Paryżu najlepsze kasztany są na placu Pigalle
+Zuzanna lubi je tylko jesienią.
diff --git a/labs04/Klasy.ipynb b/labs04/Klasy.ipynb
new file mode 100644
index 0000000..1cd0a99
--- /dev/null
+++ b/labs04/Klasy.ipynb
@@ -0,0 +1,662 @@
+{
+ "cells": [
+  {
+   "cell_type": "markdown",
+   "metadata": {
+    "collapsed": true,
+    "slideshow": {
+     "slide_type": "slide"
+    }
+   },
+   "source": [
+    "# Wprowadzenie do Pythona: Klasy\n",
+    "\n",
+    "## Tomasz Dwojak\n",
+    "\n",
+    "### 3 grudnia 2017"
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {
+    "slideshow": {
+     "slide_type": "slide"
+    }
+   },
+   "source": [
+    "# Plan na dziś:\n",
+    " * klasy,\n",
+    " * wyjątki."
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {
+    "slideshow": {
+     "slide_type": "slide"
+    }
+   },
+   "source": [
+    "## Python jest językiem obiektowym \n",
+    " * Wszystko jest obiektem: liczby, napisy, None, funkcje, moduły (biblioteki)..."
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 11,
+   "metadata": {
+    "slideshow": {
+     "slide_type": "fragment"
+    }
+   },
+   "outputs": [
+    {
+     "name": "stdout",
+     "output_type": "stream",
+     "text": [
+      "0\n",
+      "Python da się lubić !\n"
+     ]
+    }
+   ],
+   "source": [
+    "print((2017).imag)\n",
+    "print(' '.join(['Python', 'da', 'się', 'lubić', '!']))"
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {
+    "slideshow": {
+     "slide_type": "slide"
+    }
+   },
+   "source": [
+    "## Konstrukcja"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 18,
+   "metadata": {
+    "slideshow": {
+     "slide_type": "fragment"
+    }
+   },
+   "outputs": [
+    {
+     "name": "stdout",
+     "output_type": "stream",
+     "text": [
+      "<class '__main__.NajprostszaKlasa'>\n"
+     ]
+    }
+   ],
+   "source": [
+    "class NajprostszaKlasa:\n",
+    "    pass\n",
+    "\n",
+    "nasza_klasa = NajprostszaKlasa() # Uwaga na nawiasy na końcu!\n",
+    "print(type(nasza_klasa))"
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {
+    "slideshow": {
+     "slide_type": "slide"
+    }
+   },
+   "source": [
+    "## (Pseudo) Konstruktor \n",
+    "\n"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 30,
+   "metadata": {
+    "slideshow": {
+     "slide_type": "fragment"
+    }
+   },
+   "outputs": [
+    {
+     "name": "stdout",
+     "output_type": "stream",
+     "text": [
+      "2\n"
+     ]
+    }
+   ],
+   "source": [
+    "class Punkt:\n",
+    "    def __init__(self, x, y):\n",
+    "        self.x = x\n",
+    "        self.y = y\n",
+    "\n",
+    "punkt = Punkt(2, 3)\n",
+    "print(punkt.x)"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 25,
+   "metadata": {
+    "collapsed": true,
+    "slideshow": {
+     "slide_type": "slide"
+    }
+   },
+   "outputs": [],
+   "source": [
+    "class Figura:\n",
+    "    def __init__(self, vertexes):\n",
+    "        self.vertexes = vertexes\n",
+    "    \n",
+    "    def liczba_wierzcholkow(self):\n",
+    "        return len(self.vertexes)\n",
+    "    \n",
+    "    def dodaj_wierzcholek(self, x):\n",
+    "        self.vertexes.append(x)"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 26,
+   "metadata": {
+    "collapsed": true,
+    "slideshow": {
+     "slide_type": "slide"
+    }
+   },
+   "outputs": [],
+   "source": [
+    "class Prostokat(Figura):\n",
+    "    def __init__(self, vertexes):\n",
+    "        super().__init__(vertexes)\n",
+    "        \n",
+    "    def czy_jestem_kwadratem(self):\n",
+    "        pass\n",
+    "        "
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 28,
+   "metadata": {
+    "slideshow": {
+     "slide_type": "slide"
+    }
+   },
+   "outputs": [
+    {
+     "data": {
+      "text/plain": [
+       "3"
+      ]
+     },
+     "execution_count": 28,
+     "metadata": {},
+     "output_type": "execute_result"
+    }
+   ],
+   "source": [
+    "class Figura:\n",
+    "    def __init__(self, vertexes):\n",
+    "        self.vertexes = vertexes\n",
+    "    \n",
+    "    def liczba_wierzcholkow(self):\n",
+    "        return len(self.vertexes)\n",
+    "    \n",
+    "    def __len__(self):\n",
+    "        return self.liczba_wierzcholkow()\n",
+    "    \n",
+    "len(Figura([Punkt(2,3), Punkt(3,4), Punkt(0, 0)]))"
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {
+    "slideshow": {
+     "slide_type": "slide"
+    }
+   },
+   "source": [
+    "## Dobre praktyki: komentarze"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 4,
+   "metadata": {
+    "slideshow": {
+     "slide_type": "fragment"
+    }
+   },
+   "outputs": [],
+   "source": [
+    "class Punkt(object):\n",
+    "    \"\"\"Klasa reprezentująca punkt w 2D.\"\"\"\n",
+    "    def __init__(self, x, y):\n",
+    "        \"\"\"opis argumentów x i y.\"\"\"\n",
+    "        self.x = x\n",
+    "        self.y = y"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 5,
+   "metadata": {
+    "slideshow": {
+     "slide_type": "slide"
+    }
+   },
+   "outputs": [
+    {
+     "name": "stdout",
+     "output_type": "stream",
+     "text": [
+      "Help on class Punkt in module __main__:\n",
+      "\n",
+      "class Punkt(builtins.object)\n",
+      " |  Klasa reprezentująca punkt w 2D.\n",
+      " |  \n",
+      " |  Methods defined here:\n",
+      " |  \n",
+      " |  __init__(self, x, y)\n",
+      " |      opis argumentów x i y.\n",
+      " |  \n",
+      " |  ----------------------------------------------------------------------\n",
+      " |  Data descriptors defined here:\n",
+      " |  \n",
+      " |  __dict__\n",
+      " |      dictionary for instance variables (if defined)\n",
+      " |  \n",
+      " |  __weakref__\n",
+      " |      list of weak references to the object (if defined)\n",
+      "\n"
+     ]
+    }
+   ],
+   "source": [
+    "help(Punkt)"
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {
+    "slideshow": {
+     "slide_type": "slide"
+    }
+   },
+   "source": [
+    "## Enkapsulacja: publiczne czy prywatne?\n",
+    " * Prywatne zaczynają się od dwóch podkreśleń: ``__``, np. ``def __policz(self)``\n",
+    " * chronione tylko w konwencji, zaczynają się od '\\_', np. ``def _parse(self)``\n",
+    " * publiczne jest wszystko co nie zaczyna się od '\\_'."
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 6,
+   "metadata": {
+    "slideshow": {
+     "slide_type": "slide"
+    }
+   },
+   "outputs": [
+    {
+     "ename": "AttributeError",
+     "evalue": "'Parser' object has no attribute '__parse'",
+     "output_type": "error",
+     "traceback": [
+      "\u001b[0;31m---------------------------------------------------------------------------\u001b[0m",
+      "\u001b[0;31mAttributeError\u001b[0m                            Traceback (most recent call last)",
+      "\u001b[0;32m<ipython-input-6-80ee186598d3>\u001b[0m in \u001b[0;36m<module>\u001b[0;34m()\u001b[0m\n\u001b[1;32m      4\u001b[0m \u001b[0mparser\u001b[0m \u001b[0;34m=\u001b[0m \u001b[0mParser\u001b[0m\u001b[0;34m(\u001b[0m\u001b[0;34m)\u001b[0m\u001b[0;34m\u001b[0m\u001b[0m\n\u001b[1;32m      5\u001b[0m \u001b[0mparser\u001b[0m\u001b[0;34m.\u001b[0m\u001b[0m_get\u001b[0m\u001b[0;34m(\u001b[0m\u001b[0;34m)\u001b[0m\u001b[0;34m\u001b[0m\u001b[0m\n\u001b[0;32m----> 6\u001b[0;31m \u001b[0mparser\u001b[0m\u001b[0;34m.\u001b[0m\u001b[0m__parse\u001b[0m\u001b[0;34m(\u001b[0m\u001b[0;34m)\u001b[0m\u001b[0;34m\u001b[0m\u001b[0m\n\u001b[0m",
+      "\u001b[0;31mAttributeError\u001b[0m: 'Parser' object has no attribute '__parse'"
+     ]
+    }
+   ],
+   "source": [
+    "class Parser(object):\n",
+    "    def __parse(self): pass\n",
+    "    def _get(self): pass\n",
+    "parser = Parser()\n",
+    "parser._get()\n",
+    "parser.__parse()"
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {
+    "slideshow": {
+     "slide_type": "slide"
+    }
+   },
+   "source": [
+    "## Iteratory"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 7,
+   "metadata": {
+    "slideshow": {
+     "slide_type": "fragment"
+    }
+   },
+   "outputs": [
+    {
+     "name": "stdout",
+     "output_type": "stream",
+     "text": [
+      "<__main__.Punkt object at 0x7f728015b358>\n",
+      "<__main__.Punkt object at 0x7f728015b4a8>\n",
+      "<__main__.Punkt object at 0x7f728015b438>\n"
+     ]
+    }
+   ],
+   "source": [
+    "class Figura:\n",
+    "    def __init__(self, vertexes):\n",
+    "        self.vertexes = vertexes  \n",
+    "        \n",
+    "    def __iter__(self):\n",
+    "        self.index = -1\n",
+    "        return self\n",
+    "    \n",
+    "    def __next__(self):\n",
+    "        self.index += 1\n",
+    "        if self.index == len(self.vertexes):\n",
+    "            raise StopIteration\n",
+    "        return self.vertexes[self.index]\n",
+    "        \n",
+    "for v in Figura([Punkt(2,3), Punkt(3,4), Punkt(0, 0)]):\n",
+    "    print(v)"
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {
+    "collapsed": true,
+    "slideshow": {
+     "slide_type": "slide"
+    }
+   },
+   "source": [
+    "## Atrybuty i metody statyczne"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 16,
+   "metadata": {
+    "slideshow": {
+     "slide_type": "fragment"
+    }
+   },
+   "outputs": [
+    {
+     "name": "stdout",
+     "output_type": "stream",
+     "text": [
+      "0\n",
+      "0\n"
+     ]
+    }
+   ],
+   "source": [
+    "class Klasa:\n",
+    "    atrybut = 0\n",
+    "\n",
+    "klasa = Klasa()\n",
+    "print(Klasa.atrybut)\n",
+    "print(klasa.atrybut)"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 19,
+   "metadata": {
+    "slideshow": {
+     "slide_type": "slide"
+    }
+   },
+   "outputs": [
+    {
+     "name": "stdout",
+     "output_type": "stream",
+     "text": [
+      "Jestem statyczna!\n"
+     ]
+    }
+   ],
+   "source": [
+    "class Klasa:\n",
+    "    def __init__(self):\n",
+    "        self.t = 0\n",
+    "    def metoda():\n",
+    "        print(\"Jestem statyczna!\")\n",
+    "\n",
+    "Klasa.metoda()"
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {
+    "slideshow": {
+     "slide_type": "slide"
+    }
+   },
+   "source": [
+    "## Wyjątki"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 20,
+   "metadata": {
+    "slideshow": {
+     "slide_type": "fragment"
+    }
+   },
+   "outputs": [
+    {
+     "ename": "FileNotFoundError",
+     "evalue": "[Errno 2] No such file or directory: 'nieistniejący_plik.txt'",
+     "output_type": "error",
+     "traceback": [
+      "\u001b[0;31m---------------------------------------------------------------------------\u001b[0m",
+      "\u001b[0;31mFileNotFoundError\u001b[0m                         Traceback (most recent call last)",
+      "\u001b[0;32m<ipython-input-20-41928d542bef>\u001b[0m in \u001b[0;36m<module>\u001b[0;34m()\u001b[0m\n\u001b[0;32m----> 1\u001b[0;31m \u001b[0;32mwith\u001b[0m \u001b[0mopen\u001b[0m\u001b[0;34m(\u001b[0m\u001b[0;34m\"nieistniejący_plik.txt\"\u001b[0m\u001b[0;34m)\u001b[0m \u001b[0;32mas\u001b[0m \u001b[0mplik\u001b[0m\u001b[0;34m:\u001b[0m\u001b[0;34m\u001b[0m\u001b[0m\n\u001b[0m\u001b[1;32m      2\u001b[0m     \u001b[0mprint\u001b[0m\u001b[0;34m(\u001b[0m\u001b[0mplik\u001b[0m\u001b[0;34m.\u001b[0m\u001b[0mread\u001b[0m\u001b[0;34m(\u001b[0m\u001b[0;34m)\u001b[0m\u001b[0;34m)\u001b[0m\u001b[0;34m\u001b[0m\u001b[0m\n",
+      "\u001b[0;31mFileNotFoundError\u001b[0m: [Errno 2] No such file or directory: 'nieistniejący_plik.txt'"
+     ]
+    }
+   ],
+   "source": [
+    "with open(\"nieistniejący_plik.txt\") as plik:\n",
+    "    content = plik.read()"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 23,
+   "metadata": {
+    "slideshow": {
+     "slide_type": "slide"
+    }
+   },
+   "outputs": [],
+   "source": [
+    "try:\n",
+    "    with open(\"nieistniejący_plik.txt\") as plik:\n",
+    "        content = plik.read()\n",
+    "except FileNotFoundError:\n",
+    "    contenct = \"\""
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 27,
+   "metadata": {
+    "slideshow": {
+     "slide_type": "slide"
+    }
+   },
+   "outputs": [
+    {
+     "name": "stdout",
+     "output_type": "stream",
+     "text": [
+      "Warning [Errno 2] No such file or directory: 'nieistniejący_plik.txt'\n"
+     ]
+    }
+   ],
+   "source": [
+    "try:\n",
+    "    with open(\"nieistniejący_plik.txt\") as plik:\n",
+    "        content = plik.read()\n",
+    "except FileNotFoundError as e:\n",
+    "    print(\"Warning {}\".format(e))\n",
+    "    contenct = \"\""
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 28,
+   "metadata": {
+    "slideshow": {
+     "slide_type": "slide"
+    }
+   },
+   "outputs": [
+    {
+     "name": "stdout",
+     "output_type": "stream",
+     "text": [
+      "Warning [Errno 2] No such file or directory: 'nieistniejący_plik.txt'\n"
+     ]
+    }
+   ],
+   "source": [
+    "try:\n",
+    "    with open(\"nieistniejący_plik.txt\") as plik:\n",
+    "        content = plik.read()\n",
+    "except Exception as e:\n",
+    "    print(\"Warning {}\".format(e))\n",
+    "    contenct = \"\""
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 29,
+   "metadata": {
+    "collapsed": true,
+    "slideshow": {
+     "slide_type": "slide"
+    }
+   },
+   "outputs": [],
+   "source": [
+    "try:\n",
+    "    with open(\"nieistniejący_plik.txt\") as plik:\n",
+    "        content = plik.read()\n",
+    "except:\n",
+    "    contenct = \"\""
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 30,
+   "metadata": {
+    "collapsed": true,
+    "slideshow": {
+     "slide_type": "slide"
+    }
+   },
+   "outputs": [],
+   "source": [
+    "class Figura:\n",
+    "    def __init__(self, vertexes):\n",
+    "        if len(vertexes) == 0:\n",
+    "            raise Exception(\"Empty list of vertexes\")\n",
+    "        self.vertexes = vertexes"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 35,
+   "metadata": {
+    "collapsed": true,
+    "slideshow": {
+     "slide_type": "slide"
+    }
+   },
+   "outputs": [],
+   "source": [
+    "class MyError(Exception):\n",
+    "    def __init__(self, text):\n",
+    "        self.text = text\n",
+    "    def __str__(self):\n",
+    "        return self.text"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 36,
+   "metadata": {
+    "slideshow": {
+     "slide_type": "fragment"
+    }
+   },
+   "outputs": [
+    {
+     "ename": "MyError",
+     "evalue": "Coś poszło nie tak!",
+     "output_type": "error",
+     "traceback": [
+      "\u001b[0;31m---------------------------------------------------------------------------\u001b[0m",
+      "\u001b[0;31mMyError\u001b[0m                                   Traceback (most recent call last)",
+      "\u001b[0;32m<ipython-input-36-4fb306b42ebc>\u001b[0m in \u001b[0;36m<module>\u001b[0;34m()\u001b[0m\n\u001b[0;32m----> 1\u001b[0;31m \u001b[0;32mraise\u001b[0m \u001b[0mMyError\u001b[0m\u001b[0;34m(\u001b[0m\u001b[0;34m\"Coś poszło nie tak!\"\u001b[0m\u001b[0;34m)\u001b[0m\u001b[0;34m\u001b[0m\u001b[0m\n\u001b[0m",
+      "\u001b[0;31mMyError\u001b[0m: Coś poszło nie tak!"
+     ]
+    }
+   ],
+   "source": [
+    "raise MyError(\"Coś poszło nie tak!\")"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": null,
+   "metadata": {
+    "collapsed": true
+   },
+   "outputs": [],
+   "source": []
+  }
+ ],
+ "metadata": {
+  "celltoolbar": "Slideshow",
+  "kernelspec": {
+   "display_name": "Python 3",
+   "language": "python",
+   "name": "python3"
+  },
+  "language_info": {
+   "codemirror_mode": {
+    "name": "ipython",
+    "version": 3
+   },
+   "file_extension": ".py",
+   "mimetype": "text/x-python",
+   "name": "python",
+   "nbconvert_exporter": "python",
+   "pygments_lexer": "ipython3",
+   "version": "3.6.3"
+  }
+ },
+ "nbformat": 4,
+ "nbformat_minor": 2
+}
diff --git a/labs04/README.md b/labs04/README.md
new file mode 100644
index 0000000..cce5ca4
--- /dev/null
+++ b/labs04/README.md
@@ -0,0 +1,18 @@
+**ćwiczenie 1**
+Napisz funckję ``is_numeric``, która sprawdzi, czy każdy element z przekazanej listy jest typu int lub float. Wykorzystaj funcję ``isinstance()`` (https://docs.python.org/2/library/functions.html#isinstance).
+
+**ćwiczenie 2**
+Napisz prostą hierarchię klas:
+ * Klasa bazowa ``Employee``, która będzie zawierać informacje o imieniu i nazwisku pracownika. Ponadto każdy pracownik otrzyma numer ``id``, który będzie unikatowy. Wykorzystaj do tego atrybut statyczny. Napisz metodę ``get_id``, która zwraca identyfikator pracownika.
+ * Klasy pochodna:  ``Recruiter``, która ma dodatkową mtodę ``recruit``, która jako parament przyjmuje obiekt ``Employee`` i zapisuje jego ``id`` w liście ``self.recruited``.
+ * Klasa pochodna ``Programmer``. Klasa ``Programmer`` ma przyjąć w konstruktorze podstawowe informacje (imię i nazwisko) oraz obiekt rekturera. Ponadto stwórz  atrybut ``recruiter``, który będzie przechowywać ``id`` rekrutera.
+
+**ćwiczenie 3 (zadanie domowe) **
+Stwórz klasę ``Point``, która będzie reprezentować punkt w przestrzeni wielowymiarowej:
+ * Konstruktor ma przyjąc tylko 1 parametr: listę współrzednych. Wykorzystaj funkcję z pierwszego zadania, żeby sprawdzić, czy lista zawiera wyłącznie liczby.
+ * Napisz metodę add, która dida dwa punkty po współrzędnych i zwróci obiekt typu ``Punkt``. Zaimplementuj własny wyjątek ``DimensionError``, który zostaje wyrzucony, jeżeli dodawany punkt ma inny wymiar.
+ * Napisz metodę ``to\_string``, która zwróci łancuch znakowy, który w czytelny sposób przedstawi punkt.
+ * Napisz metodę __len__, która zwróci liczbę współrzędnych punktu. Zobacz, czy możesz teraz wywołać funkcję len na obiekcie typy punkt.
+ * Napisz metodę __str__, która bedzie działać dokładnie tak samo jak metoda ``to_string``. Wyświetl obiekt typy Point korzystając z funkcji print.
+
+
diff --git a/labs04/task01.py b/labs04/task01.py
new file mode 100644
index 0000000..88741a4
--- /dev/null
+++ b/labs04/task01.py
@@ -0,0 +1,3 @@
+#!/usr/bin/env python2
+# -*- coding: utf-8 -*-
+
diff --git a/labs04/task02.py b/labs04/task02.py
new file mode 100644
index 0000000..88741a4
--- /dev/null
+++ b/labs04/task02.py
@@ -0,0 +1,3 @@
+#!/usr/bin/env python2
+# -*- coding: utf-8 -*-
+
diff --git a/labs04/task03.py b/labs04/task03.py
new file mode 100644
index 0000000..88741a4
--- /dev/null
+++ b/labs04/task03.py
@@ -0,0 +1,3 @@
+#!/usr/bin/env python2
+# -*- coding: utf-8 -*-
+